stucco on brick

I just inspected a home on the north side of Chicago I’m estimating 60-70 yrs old. It ha an “English basement” about 3 1/2 ft. below grade. It had a concrete foundation up to grade with a brick exterior wall reaching the bottom of the 1st floor. From the inside of the basement the brick was coated with stucco. There were several spots where the stucco was flaking off, indicative of moisture penetration. The spots where the stucco peeled off, the brick was heavily coated with a white cotton like material. Underneath this material the brick was deteriorating significantly. I think the problem is moisture penetration but would anyone know what the white cotton like material may be?

Any pictures?

Possibly efflorescense.

Without photos try searching here

sorry- no pictures

When you touched the white cotton, did it turn to powder on you finger? That’s efflorescense.